Evaluation of High-Performance PET Scanner

All data were taken on the PennPET Explorer, a 70-cm long AFOV PET scanner built using the Philips digital photon counting tiles, which consist of an array of 3.86 × 3.86 × 19 mm³ LYSO crystals coupled to a digital SiPM array. The scanner is composed of three 23-cm AFOV rings, of which 6.6-cm is currently inactive due to data readout limitations (Figure 1C), unlike the simulated scanner that did not have inactive regions. The inactive regions result in half the total sensitivity and introduce small axial image noise variations. Once these regions are active, the scanner will match the simulated 70-cm scanner. The PennPET Explorer has a measured spatial resolution of 4.0 mm, energy resolution of 12%, sensitivity of 54 kcps/MBq, and a timing resolution of 250 ps. The timing resolution is improved compared to the Philips Vereos by cooling the system to 5°C, thus reducing the dark noise, and using a lower timing trigger level [19 (link)].